This invention relates to a method for manufacturing semiconductor device with an energy beam-converging section.
To supplement the decline in yield of a semiconductor memory due to high density and large-scale integration, it is widely accepted to use a redundancy technique of providing not only a main circuit but also redundant elements in order to prevent the main circuit from being disabled by the presence of a defective portion. According to this redundancy technique, a switching section for substituting the defective section of the main circuit for one of the redundant elements is provided. Later, laser beams, for example, are used to actuate said switching section. The technique of radiating the laser beams is set forth, for example, in "Reliability of LSI Memory Circuits Exposed to Laser Cutting" by Myron J. Rand, IEEE International Reliability Physics Symposium, 17th Annual Proceedings, 1979. However, this proposed laser beam-emitting technique has the drawbacks that when a large number of switching sections have to be actuated, it is necessary to align the focus of the laser device with the switching sections with high precision. This operation is generally accompanied with difficulties. For the accurate alignment of the focus of the laser device lens with the respective switching sections, it is necessary to provide a high precision locating mechanism, thereby increasing the cost of the energy beam-converging device.